Wildlife & Habitat
Coral communities at Rose include about 140 species, after surveys through 2007, and are distinctive and quite different from those of the other islands in Samoa. Coral cover, abundance, species richness, and diversity are moderate compared to other reefs in the archipelago, but high compared to the Hawaiian Islands. Dominant corals at Rose include Favia, Acropora, Porites, Montipora, Astreopora, Montastrea, and Pocillopora. About 20 species and 6 genera of corals observed in 1994 at Rose were not seen during 2002, perhaps due to a combination of a bleaching event, shipgrounding, and other factors (crown-of-starfish predation, hurricanes, tsunami waves, etc.). More recent surveys in 2002, and 2004-2007 reveal that coral recovery is proceeding rapidly following complete removal of ship debris and the earlier insults of the ship grounding, coral bleaching and several large wave events.
Despite its small size, Rose supports the largest populations of giant clams, nesting sea turtles, nesting seabirds, and rare species of reef fish in American Samoa. In 2002, fish densities at Rose Atoll were higher than at other American Samoa islands, but only about half those found in the Northwestern Hawaiian Islands. Giant clams are most abundant on the bottoms of the pinnacles in the lagoon. The fish communities at Rose are also distinct from others in the Samoan Archipelago.
To date, about 270 species of fish have been recorded and surveys have indicated little change in the reef fish community in the past 15 years. Pelagic fish species found outside the lagoon include various species of tuna, barracuda, mahimahi, billfish, and sharks. Deep diving submersible surveys in 2005 sponsored by the Hawaii Undersea Research Laboratory and U.S. Fish and Wildlife Service revealed a plethora of species and life forms not observed at shallow depths including tunicates, stalked crinoids, many fish, and unusual sea stars. One new species of cardinal fish (Ostorhinchus leslie) was recently discovered at the atoll in the shallow part of the lagoon.
The two islands
at Rose Atoll are important nesting sites for the threatened green turtle
in American Samoa. Satellite tags attached to the nesting green turtles
at Rose have shown that these turtles migrate between American Samoa
and other Pacific island nations (i.e., Fiji and French Polynesia).
In addition to the migratory breeding population of turtles at the atoll
during the nesting season (August to February), a small resident population
of juveniles apparently lives on the atoll. Endangered hawksbill turtles
have also been seen in the
Rose Atoll is the most important seabird colony in the region, since approximately 97 percent of the seabird population of American Samoa resides on Rose. The two islands provide important nesting and roosting habitat for 12 species of federally protected migratory seabirds including terns, noddies, boobies, frigatebirds, and tropicbirds. Only 1 year after removal of rats in 1993, two species of shearwaters (wedge-tailed and Christmas Island) were sighted on Rose Island, the first such burrowing seabirds recorded on Rose. Additionally, five species of federally protected migratory shorebirds and one species of forest bird, the long-tailed cuckoo (a migrant from New Zealand), use the atoll for feeding resting, and roosting.